Asynchronous data store operations

ABSTRACT

A processing system server and methods with the server to provide data values. The server maintains a cache of objects. The server executes an asynchronous computation to determine the value of an object. In response to a request for the object before the asynchronous computation has determined the value of the object, returning a value of the object from the cache. In response to a request for the object after the asynchronous computation has determined the value of the object, returning a value of the object determined by the asynchronous computation.

BACKGROUND

The present invention generally relates to data caching in computersystems. Data storage can have significant latency. This is particularlytrue for cloud storage where the latency for fetching and storing datain the cloud can be high due to the fact that the storage server can beremote from the client. A method is needed to reduce the latency of datastore operations.

BRIEF SUMMARY

According to various embodiments, disclosed is a processing systemcomprised of a server, and a method for the server to provide datavalues comprises: the server maintaining a cache of objects; the serverexecuting an asynchronous computation to determine the value of anobject; in response to a request for the object before the asynchronouscomputation has determined the value of the object, returning a value ofthe object from the cache; and in response to a request for the objectafter the asynchronous computation has determined the value of theobject, returning a value of the object determined by the asynchronouscomputation.

The present invention according to various embodiments thereof, providesa processing system comprising: a server; persistent memory; a networkinterface device for communicating with one or more networks; and atleast one processor, communicatively coupled with the server, thepersistent memory, and the network interface device, the at least oneprocessor, responsive to executing computer instructions, for performingoperations comprising: the server maintaining a cache of objects in thepersistent memory; the server executing an asynchronous computation todetermine the value of an object; in response to a request for theobject before the asynchronous computation has determined the value ofthe object, returning a value of the object from the cache of objects;and in response to a request for the object after the asynchronouscomputation has determined the value of the object, returning a value ofthe object determined by the asynchronous computation.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures wherein reference numerals refer to identicalor functionally similar elements throughout the separate views, andwhich together with the detailed description below are incorporated inand form part of the specification, serve to further illustrate variousembodiments and to explain various principles and advantages all inaccordance with the present invention, in which:

FIG. 1 is a block diagram illustrating an example of a client-serversystem, according to an embodiment of the present invention;

FIG. 2 is a block diagram illustrating an example of a method forasynchronous data store operations, according to an embodiment of thepresent invention;

FIG. 3 is a block diagram illustrating an example processing systemserver node, according to an embodiment of the present invention;

FIG. 4 depicts a cloud computing environment suitable for use in anembodiment of the present invention; and

FIG. 5 depicts abstraction model layers according to the cloud computingembodiment of FIG. 4.

DETAILED DESCRIPTION

As required, detailed embodiments are disclosed herein; however, it isto be understood that the disclosed embodiments are merely examples andthat the systems and methods described below can be embodied in variousforms. Therefore, specific structural and functional details disclosedherein are not to be interpreted as limiting, but merely as a basis forthe claims and as a representative basis for teaching one skilled in theart to variously employ the present subject matter in virtually anyappropriately detailed structure and function. Further, the terms andphrases used herein are not intended to be limiting, but rather, toprovide an understandable description of the concepts.

The description of the present invention has been presented for purposesof illustration and description, but is not intended to be exhaustive orlimited to the invention in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the invention. Theembodiments were chosen and described in order to best explain theprinciples of the invention and the practical application, and to enableothers of ordinary skill in the art to understand the invention forvarious embodiments with various modifications as are suited to theparticular use contemplated. The terminology used herein is for thepurpose of describing particular embodiments only and is not intended tobe limiting of the invention.

Various embodiments of the present invention are applicable to cachingin a wide variety of environments including cloud environments andnon-cloud environments. FIG. 1 shows a server processing system inaccordance with the current invention.

A first server 101 is accessing data from at least one other server 103.The at least one other server 103 may comprise one server or multipleservers. It may take considerable time for the first server 101 to querythe at least one other server 103. Therefore, the first server 101contains a local cache 102 for storing data fetched from the at leastone other server 103. Information can be retrieved considerably fasterfrom the local cache 102 than from a remote at least one other server103. The local cache 102 can thus improve performance

One problem is that data fetched from the local cache 102 may not becurrent. The present invention provides methods and systems foralleviating this problem.

FIG. 2 shows an example method for obtaining data from at least oneother server 103, in accordance with the invention. The local cache 102,according to this example, is continuously maintained in step 201. Thelocal cache 102 contains data from at least one other server 103.Suppose that object o1 is an important object stored on at least oneother server 103 which is needed by the first server 101. In step 202,the first server 101 creates an asynchronous computation f1 to fetchobject o1 from the at least one other server 103. An asynchronouscomputation may be a thread or process which can run in parallel withexisting computations and not block them. One example of an asynchronouscomputation is a future. Futures are used to represent the result ofasynchronous computations which may not have finished executing. Severalprogramming languages implement them, such as Java.

For this example, more functionality is provided by ListenableFuture.

There are several types of events which might trigger the method step202 to create an asynchronous computation f1 to fetch object o1. Forexample, a request for object o1 might trigger the method step 202 tocreate an asynchronous computation f1 to fetch object o1. The methodstep 202 might be invoked periodically. For example, the method step 202might be invoked after a period of time (i.e., a time interval) haselapsed. If data is available on how frequently object o1 changes, thiscan be used to determine when to invoke the method step 202 to create anasynchronous computation f1 to fetch object o1. If object o1 changesfrequently, then it may be desired to invoke the method step 202frequently. If object o1 changes less frequently, then it may beadvisable to invoke the method step 202 less frequently to reduceoverhead.

The importance of having current values of object o1 can also be used inmaking decisions of how frequently to invoke step 202. If it isimportant to have current values of object o1, then the method step 202might be invoked more frequently. If it is less important to havecurrent values of object o1, then the method step 202 might be invokedless frequently.

Now suppose, according to the example, that a request for object o1 isreceived before asynchronous computation f1 has fetched object o1 fromthe at least one other server 103 (Step 203). In this case, in step 205,the value o1 object o1 from cache 102 is returned, if it exists.

In step 204, according to the example, a request for object o1 isreceived after asynchronous computation f1 has fetched object o1 fromthe at least one other server 103. In this case, in step 206, the valueof object o1 fetched from the at least one other server 103 byasynchronous computation f1 is returned.

Once the asynchronous computation f1 has fetched object o1 from the atleast one other server 103, the first server 101 can optionally updatethe cache 102 with the updated value of object o1 fetched from the atleast one other server 103 by the asynchronous computation f1.

Asynchronous computations such as threads, processes, futures, etc., canalso be used to store data on the at least one other server 103. Thatway, computations will not be blocked waiting for a remote storeoperation to complete. For example, the first server 101 can invoke afuture f2 to store an object o2 on the at least one other server 103.Existing computations can continue to execute before the future f2completes the store operation.

Once the future f2 has stored object o2 on the at least one other server103, the first server 101 can optionally update the cache 102 with thevalue of object o2 stored on the at least one other server 103 by thefuture f2.

An asynchronous computation for determining the value of an object mighthave to do sophisticated computations. For example, it might becomputationally expensive to compute a value for an object. Determiningthe value of an object may involve accessing several databases which canconsume significant latency.

In some cases, the at least one other server 103 may comprise two ormore servers. If the first server 101 makes a request to the at leastone other server 103 for object o3, multiple servers comprising the atleast one other server 103 may return different values for object o3. Inthis case, according to the example, an asynchronous computation f3determining the value of object o3 makes a determination of whichvalue(s) to return for object o3. There are multiple ways that this canbe done:

The asynchronous computation f3 can see which values for object o3appear most frequently. For example, suppose that the asynchronouscomputation f3 receives three values for object o3: 300, 200, and 200.Since the value 200 appears most frequently, 200 is the value that isreturned.

Time stamps, according to various embodiments, can be associated withthe values returned from the servers. In this case, the asynchronouscomputation f3 returns a value with a most recent time stamp.

Below will be discussed, by examples, further details of how futures canbe used to implement various embodiments of the invention in Javaprogramming language. Other programming languages with futures can beused as well. In Java, as an example, a Future represents the result ofan asynchronous computation. Methods are provided to check if thecomputation is complete, to wait for its completion, and to retrieve theresult of the computation.

Suppose that objects are referenced by keys. A request is made to fetcha value for an object corresponding to “key1” via a method call:

MultiValue mv1=lookup(“key1”);

Class MultiValue includes the following fields:

cachedVal: value fetched from the cache 102 (if it exists). The lookupmethod will not return until the cache lookup has taken place. In somecases, “key1” may not correspond to any value in the cache in which casecachedVal is set to a not found value.

storeValueFuture: future used to request the value of “key1” from the atleast one other server 103. A separate thread is used for this future.The lookup method does not wait for this thread to complete beforereturning, allowing the main computation to continue executing withoutblocking.

mv1 has a getFast( ) method for returning a value quickly, and can beimplemented using:

If (!storeValueFuture.isDone( )==&& (cachedVal. exists( )) then

return cachedVal.value( );

else

return storeValueFuture.get( );

If the storeValueFuture has not finished executing and a cached value(stored in cachedVal) exists, getFast( ) will return the cached valueright away without blocking. After the future has completed, getFast( )will return the value fetched from the at least one other server 103.

Using this approach, the program can use mv1.cachedVal for the valuecorresponding to “key1” before storeValueFuture has finished executing.After storeValueFuture has finished executing, the program can use thevalue returned by storeValueFuture for the value corresponding to“key1”. In addition, an error handling method can be provided which isinvoked if the lookup operation in the at least one other server 103fails. If ListenableFutures are used, a callback function in theapplication can be provided which will execute as soon asstoreValueFuture has finished executing.

In some cases, it is desirable to get a value from the at least oneother server 103, even if this means waiting for the operation tocomplete. This can be achieved by invoking my1.getFromServer( ) which isimplemented as:

return storeValueFuture.get( );

Java also has ListenableFutures. ListenableFuture extends the JavaFuture interface allowing callback computations to be executed after thefuture has completed execution. Using ListenableFutures, the lookupmethod can be implemented so that the cache is automatically updatedafter the asynchronous computation fetching the value of “key1” from theat least one other server 103 has finished executing.

Now, consider a request to store object7 with key “key1” in the at leastone other server 103:

future1=dataStore.putAsync(“key1”, object7);

The computation does not block waiting for the putAsync operation tocomplete. The computation can thus proceed without blocking. We candetermine when the write to the at least one other server 103 hascompleted via:

future1.isDone( );

which returns true if the write to the at least one other server 103 hascompleted. If future 1 is a ListenableFuture, a callback can be used toupdate the cache 102 after the write to the at least one other server103 has completed.

Alternatively, putAsync can cache object7 immediately without waitingfor the write to the at least one other server 103 to complete. This isdone synchronously, so execution does not proceed until object7 has beencached. putAsync also creates a future to store object7 in the at leastone other server 103. This future is then returned by putAsync asfuture1, and the application program continues executing without waitingfor the future to finish storing object7 in the at least one otherserver 103. If the object corresponding to “key1” is requested beforeobject7 is stored in the at least one other server 103, object7 can beobtained from the cache 102.

An error handling method can be provided which is invoked if storingobject 7 in the at least one other server 103 fails. If object7 is notsuccessfully stored in the at least one other server 103, the errorhandling method can be used to retry the store operation.

Example of a Processing System Server Node Operating in a Network

FIG. 3 illustrates an example of a processing system server node 300(also referred to as a computer system/server or referred to as a servernode) suitable for use according to the client-server system exampleshown in FIG. 1. The server node 300, according to the example, iscommunicatively coupled with a cloud infrastructure 332 that can includeone or more communication networks. The cloud infrastructure 332 iscommunicatively coupled with a storage cloud 334 (which can include oneor more storage servers) and with a computation cloud 336 (which caninclude one or more computation servers). This simplified example is notintended to suggest any limitation as to the scope of use or function ofvarious example embodiments of the invention described herein.

The server node 300 comprises a computer system/server, which isoperational with numerous other general purpose or special purposecomputing system environments or configurations. Examples of well-knowncomputing systems, environments, and/or configurations that may besuitable for use with such a computer system/server include, but are notlimited to, personal computer systems, server computer systems, thinclients, thick clients, hand-held or laptop devices, multiprocessorsystems, microprocessor-based systems, set top boxes, programmableconsumer electronics, network PCs, minicomputer systems, mainframecomputer systems, and distributed cloud computing environments thatinclude any of the above systems and/or devices, and the like.

The computer system/server 300 may be described in the general contextof computer system-executable instructions, such as program modules,being executed by a computer system. Generally, program modules mayinclude routines, programs, objects, components, logic, data structures,and so on that perform particular tasks or implement particular abstractdata types. Computer system/server may be practiced in distributed cloudcomputing environments where tasks are performed by remote processingdevices that are linked through a communications network. In adistributed cloud computing environment, program modules may be locatedin both local and remote computer system storage media including memorystorage devices.

Referring more particularly to FIG. 3, the following discussion willdescribe a more detailed view of an example cloud infrastructure servernode embodying at least a portion of the client-server system of FIG. 1.According to the example, at least one processor 302 is communicativelycoupled with system main memory 304 and persistent memory 306.

A bus architecture 308 facilitates communicatively coupling between theat least one processor 302 and the various component elements of theserver node 300. The bus 308 represents one or more of any of severaltypes of bus structures, including a memory bus or memory controller, aperipheral bus, an accelerated graphics port, and a processor or localbus using any of a variety of bus architectures. By way of example, andnot limitation, such architectures include Industry StandardArchitecture (ISA) bus, Micro Channel Architecture (MCA) bus, EnhancedISA (EISA) bus, Video Electronics Standards Association (VESA) localbus, and Peripheral Component Interconnects (PCI) bus.

The system main memory 304, in one embodiment, can include computersystem readable media in the form of volatile memory, such as randomaccess memory (RAM) and/or cache memory. By way of example only, apersistent memory storage system 306 can be provided for reading fromand writing to a non-removable, non-volatile magnetic media (not shownand typically called a “hard drive”). Although not shown, a magneticdisk drive for reading from and writing to a removable, non-volatilemagnetic disk (e.g., a “floppy disk”), and an optical disk drive forreading from or writing to a removable, non-volatile optical disk suchas a CD-ROM, DVD-ROM or other optical media can be provided. In suchinstances, each can be connected to bus 308 by one or more data mediainterfaces. As will be further depicted and described below, persistentmemory 306 may include at least one program product having a set (e.g.,at least one) of program modules that are configured to carry out thefunctions of various embodiments of the invention.

Program/utility, having a set (at least one) of program modules, may bestored in persistent memory 306 by way of example, and not limitation,as well as an operating system 324, one or more application programs326, other program modules, and program data. Each of the operatingsystem 324, one or more application programs 326, other program modules,and program data, or some combination thereof, may include animplementation of a networking environment. Program modules generallymay carry out the functions and/or methodologies of various embodimentsof the invention as described herein.

The at least one processor 302 is communicatively coupled with one ormore network interface devices 316 via the bus architecture 308. Thenetwork interface device 316 is communicatively coupled, according tovarious embodiments, with one or more networks operably coupled with acloud infrastructure 332. The cloud infrastructure 332 includes astorage cloud 334, which comprises one or more storage servers (or alsoreferred to as storage server nodes), and a computation cloud 336, whichcomprises one or more computation servers (or also referred to ascomputation server nodes). The network interface device 316 cancommunicate with one or more networks such as a local area network(LAN), a general wide area network (WAN), and/or a public network (e.g.,the Internet). The network interface device 316 facilitatescommunication between the server node 300 and other server nodes in thecloud infrastructure 332.

A user interface 310 is communicatively coupled with the at least oneprocessor 302, such as via the bus architecture 308. The user interface310, according to the present example, includes a user output interface312 and a user input interface 314. Examples of elements of the useroutput interface 312 can include a display, a speaker, one or moreindicator lights, one or more transducers that generate audibleindicators, and a haptic signal generator. Examples of elements of theuser input interface 314 can include a keyboard, a keypad, a mouse, atrack pad, a touch pad, and a microphone that receives audio signals.The received audio signals, for example, can be converted to electronicdigital representation and stored in memory, and optionally can be usedwith voice recognition software executed by the processor 302 to receiveuser input data and commands

A computer readable medium reader/writer device 318 is communicativelycoupled with the at least one processor 302. The reader/writer device318 is communicatively coupled with a computer readable medium 320. Theserver node 300, according to various embodiments, can typically includea variety of computer readable media 320. Such media may be anyavailable media that is accessible by the computer system/server 300,and it can include any one or more of volatile media, non-volatilemedia, removable media, and non-removable media.

Computer instructions 307 can be at least partially stored in variouslocations in the server node 300. For example, at least some of theinstructions 307 may be stored in any one or more of the following: inan internal cache memory in the one or more processors 302, in the mainmemory 304, in the persistent memory 306, and in the computer readablemedium 320.

The instructions 307, according to the example, can include computerinstructions, data, configuration parameters, and other information thatcan be used by the at least one processor 302 to perform features andfunctions of the server node 300. According to the present example, theinstructions 307 include an operating system 324, one or moreapplications 326, a set of ListenableFuture methods 328 and a set ofMutiValue methods 330 as has been discussed above with reference toFIGS. 1 and 2. Additionally, the instructions 307 include server nodeconfiguration data.

The at least one processor 302, according to the example, iscommunicatively coupled with the server cache storage 322 (also referredto as local cache), which can store at least a portion of the servernode data, networking system and cloud infrastructure messages and databeing communicated with the server node 300, and other data, foroperation of services and applications coupled with the server node 300.Various functions and features of the present invention, as have beendiscussed above, may be provided with use of the server node 300.

Example Cloud Computing Environment

It is understood in advance that although this disclosure includes adetailed description on cloud computing, implementation of the teachingsrecited herein are not limited to a cloud computing environment. Rather,embodiments of the present invention are capable of being implemented inconjunction with any other type of computing environment now known orlater developed.

Cloud computing is a model of service delivery for enabling convenient,on-demand network access to a shared pool of configurable computingresources (e.g. networks, network bandwidth, servers, processing,memory, storage, applications, virtual machines, and services) that canbe rapidly provisioned and released with minimal management effort orinteraction with a provider of the service. This cloud model may includeat least five characteristics, at least three service models, and atleast four deployment models.

Characteristics are as follows:

On-demand self-service: a cloud consumer can unilaterally provisioncomputing capabilities, such as server time and network storage, asneeded automatically without requiring human interaction with theservice's provider.

Broad network access: capabilities are available over a network andaccessed through standard mechanisms that promote use by heterogeneousthin or thick client platforms (e.g., mobile phones, laptops, and PDAs).

Resource pooling: the provider's computing resources are pooled to servemultiple consumers using a multi-tenant model, with different physicaland virtual resources dynamically assigned and reassigned according todemand There is a sense of location independence in that the consumergenerally has no control or knowledge over the exact location of theprovided resources but may be able to specify location at a higher levelof abstraction (e.g., country, state, or datacenter).

Rapid elasticity: capabilities can be rapidly and elasticallyprovisioned, in some cases

automatically, to quickly scale out and rapidly released to quicklyscale in. To the consumer, the capabilities available for provisioningoften appear to be unlimited and can be purchased in any quantity at anytime.

Measured service: cloud systems automatically control and optimizeresource use by leveraging a metering capability at some level ofabstraction appropriate to the type of service (e.g., storage,processing, bandwidth, and active user accounts). Resource usage can bemonitored, controlled, and reported providing transparency for both theprovider and consumer of the utilized service.

Service Models are as follows:

Software as a Service (SaaS): the capability provided to the consumer isto use the provider's applications running on a cloud infrastructure.The applications are accessible from various client devices through athin client interface such as a web browser (e.g., web-based e-mail).The consumer does not manage or control the underlying cloudinfrastructure including network, servers, operating systems, storage,or even individual application capabilities, with the possible exceptionof limited user-specific application configuration settings.

Platform as a Service (PaaS): the capability provided to the consumer isto deploy onto the cloud infrastructure consumer-created or acquiredapplications created using programming languages and tools supported bythe provider. The consumer does not manage or control the underlyingcloud infrastructure including networks, servers, operating systems, orstorage, but has control over the deployed applications and possiblyapplication hosting environment configurations.

Infrastructure as a Service (IaaS): the capability provided to theconsumer is to provision processing, storage, networks, and otherfundamental computing resources where the consumer is able to deploy andrun arbitrary software, which can include operating systems andapplications. The consumer does not manage or control the underlyingcloud infrastructure but has control over operating systems, storage,deployed applications, and possibly limited control of select networkingcomponents (e.g., host firewalls).

Deployment Models are as follows:

Private cloud: the cloud infrastructure is operated solely for anorganization. It may be managed by the organization or a third party andmay exist on-premises or off-premises.

Community cloud: the cloud infrastructure is shared by severalorganizations and supports a specific community that has shared concerns(e.g., mission, security requirements, policy, and complianceconsiderations). It may be managed by the organizations or a third partyand may exist on-premises or off-premises.

Public cloud: the cloud infrastructure is made available to the generalpublic or a large industry group and is owned by an organization sellingcloud services.

Hybrid cloud: the cloud infrastructure is a composition of two or moreclouds (private,

community, or public) that remain unique entities but are bound togetherby standardized or proprietary technology that enables data andapplication portability (e.g., cloud bursting for load-balancing betweenclouds).

A cloud computing environment is service oriented with a focus onstatelessness, low coupling, modularity, and semantic interoperability.At the heart of cloud computing is an infrastructure comprising anetwork of interconnected nodes.

Referring now to FIG. 4, an illustrative cloud computing environment 450is depicted. As shown, cloud computing environment 450 comprises one ormore cloud computing nodes 410 with which local computing devices usedby cloud consumers, such as, for example, personal digital assistant(PDA) or cellular telephone 454A, desktop computer 454B, laptop computer454C, and/or automobile computer system 454N may communicate. Nodes 410may communicate with one another. They may be grouped (not shown)physically or virtually, in one or more networks, such as Private,Community, Public, or Hybrid clouds, or a combination thereof. Thisallows cloud computing environment 450 to offer infrastructure,platforms and/or software as services for which a cloud consumer doesnot need to maintain resources on a local computing device. It isunderstood that the types of computing devices 454A-N shown in FIG. 4are intended to be illustrative only and that computing nodes 410 andcloud computing environment 450 can communicate with any type ofcomputerized device over any type of network and/or network addressableconnection (e.g., using a web browser).

Referring now to FIG. 5, a set of functional abstraction layers providedby cloud computing environment 450 is shown. It should be understood inadvance that the components, layers, and functions shown in FIG. 5 areintended to be illustrative only and embodiments of the invention arenot limited thereto. As depicted, the following layers and correspondingfunctions are provided:

Hardware and software layer 560 includes hardware and softwarecomponents. Examples of hardware components include: mainframes 561;RISC (Reduced Instruction Set Computer) architecture based servers 562;servers 563; blade servers 564; storage devices 565; and networks andnetworking components 566. In some embodiments, software componentsinclude network application server software 567 and database software568.

Virtualization layer 570 provides an abstraction layer from which thefollowing examples of virtual entities may be provided: virtual servers571; virtual storage 572; virtual networks 573, including virtualprivate networks; virtual applications and operating systems 574; andvirtual clients 575.

In one example, management layer 580 may provide the functions describedbelow. Resource provisioning 581 provides dynamic procurement ofcomputing resources and other resources that are utilized to performtasks within the cloud computing environment. Metering and Pricing 582provide cost tracking of resources which are utilized within the cloudcomputing environment, and billing or invoicing for consumption of theseresources. In one example, these resources may comprise applicationsoftware licenses. Security provides identity verification for cloudconsumers and tasks, as well as protection for data and other resources.User portal 583 provides access to the cloud computing environment forconsumers and system administrators. Service level management 584provides cloud computing resource allocation and management such thatrequired service levels are met. Service Level Agreement (SLA) planningand fulfillment 585 provide pre-arrangement for, and procurement of,cloud computing resources for which a future requirement is anticipatedin accordance with an SLA.

Workloads layer 590 provides examples of functionality for which thecloud computing environment may be utilized. Examples of workloads andfunctions which may be provided from this layer include: mapping andnavigation 591; software development and lifecycle management 592;virtual classroom education delivery 593; data analytics processing 594;transaction processing 595; and other data communication and deliveryservices 596. Various functions and features of the present invention,as have been discussed above, may be provided with use of a server node300 communicatively coupled with a cloud infrastructure 332, which caninclude a storage cloud 334 and/or a computation cloud 336.

Non-Limiting Examples

The present invention may be a system, a method, and/or a computerprogram product at any possible technical detail level of integration.The computer program product may include a computer readable storagemedium (or media) having computer readable program instructions thereonfor causing a processor to carry out aspects of the present invention.

The computer readable storage medium can be a tangible device that canretain and store instructions for use by an instruction executiondevice. The computer readable storage medium may be, for example, but isnot limited to, an electronic storage device, a magnetic storage device,an optical storage device, an electromagnetic storage device, asemiconductor storage device, or any suitable combination of theforegoing. A non-exhaustive list of more specific examples of thecomputer readable storage medium includes the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a static random access memory (SRAM), a portablecompact disc read-only memory (CD-ROM), a digital versatile disk (DVD),a memory stick, a floppy disk, a mechanically encoded device such aspunch-cards or raised structures in a groove having instructionsrecorded thereon, and any suitable combination of the foregoing. Acomputer readable storage medium, as used herein, is not to be construedas being transitory signals per se, such as radio waves or other freelypropagating electromagnetic waves, electromagnetic waves propagatingthrough a waveguide or other transmission media (e.g., light pulsespassing through a fiber-optic cable), or electrical signals transmittedthrough a wire.

Computer readable program instructions described herein can bedownloaded to respective computing/processing devices from a computerreadable storage medium or to an external computer or external storagedevice via a network, for example, the Internet, a local area network, awide area network and/or a wireless network. The network may comprisecopper transmission cables, optical transmission fibers, wirelesstransmission, routers, firewalls, switches, gateway computers and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives computer readable programinstructions from the network and forwards the computer readable programinstructions for storage in a computer readable storage medium withinthe respective computing/processing device.

Computer readable program instructions for carrying out operations ofthe present invention may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, configuration data for integrated circuitry, oreither source code or object code written in any combination of one ormore programming languages, including an object oriented programminglanguage such as Smalltalk, C++, or the like, and procedural programminglanguages, such as the “C” programming language or similar programminglanguages. The computer readable program instructions may executeentirely on the user's computer, partly on the user's computer, as astand-alone software package, partly on the user's computer and partlyon a remote computer or entirely on the remote computer or server. Inthe latter scenario, the remote computer may be connected to the user'scomputer through any type of network, including a local area network(LAN) or a wide area network (WAN), or the connection may be made to anexternal computer (for example, through the Internet using an InternetService Provider). In some embodiments, electronic circuitry including,for example, programmable logic circuitry, field-programmable gatearrays (FPGA), or programmable logic arrays (PLA) may execute thecomputer readable program instructions by utilizing state information ofthe computer readable program instructions to personalize the electroniccircuitry, in order to perform aspects of the present invention.

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer readable program instructions.

These computer readable program instructions may be provided to aprocessor of a general purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the blocks may occur out of theorder noted in the Figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

Although the present specification may describe components and functionsimplemented in the embodiments with reference to particular standardsand protocols, the invention is not limited to such standards andprotocols. Each of the standards represents examples of the state of theart. Such standards are from time-to-time superseded by faster or moreefficient equivalents having essentially the same functions.

The illustrations of examples described herein are intended to provide ageneral understanding of the structure of various embodiments, and theyare not intended to serve as a complete description of all the elementsand features of apparatus and systems that might make use of thestructures described herein. Many other embodiments will be apparent tothose of skill in the art upon reviewing the above description. Otherembodiments may be utilized and derived therefrom, such that structuraland logical substitutions and changes may be made without departing fromthe scope of this invention. Figures are also merely representationaland may not be drawn to scale. Certain proportions thereof may beexaggerated, while others may be minimized. Accordingly, thespecification and drawings are to be regarded in an illustrative ratherthan a restrictive sense.

Although specific embodiments have been illustrated and describedherein, it should be appreciated that any arrangement calculated toachieve the same purpose may be substituted for the specific embodimentsshown. The examples herein are intended to cover any and all adaptationsor variations of various embodiments. Combinations of the aboveembodiments, and other embodiments not specifically described herein,are contemplated herein.

The Abstract is provided with the understanding that it is not intendedbe used to interpret or limit the scope or meaning of the claims. Inaddition, in the foregoing Detailed Description, various features aregrouped together in a single example embodiment for the purpose ofstreamlining the disclosure. This method of disclosure is not to beinterpreted as reflecting an intention that the claimed embodimentsrequire more features than are expressly recited in each claim. Rather,as the following claims reflect, inventive subject matter lies in lessthan all features of a single disclosed embodiment. Thus the followingclaims are hereby incorporated into the Detailed Description, with eachclaim standing on its own as a separately claimed subject matter.

Although only one processor is illustrated for an information processingsystem, information processing systems with multiple CPUs or processorscan be used equally effectively. Various embodiments of the presentinvention can further incorporate interfaces that each includesseparate, fully programmed microprocessors that are used to off-loadprocessing from the processor. An operating system included in mainmemory for a processing system may be a suitable multitasking and/ormultiprocessing operating system, such as, but not limited to, any ofthe Linux, UNIX, Windows, and Windows Server based operating systems.Various embodiments of the present invention are able to use any othersuitable operating system. Various embodiments of the present inventionutilize architectures, such as an object oriented framework mechanism,that allow instructions of the components of the operating system to beexecuted on any processor located within an information processingsystem. Various embodiments of the present invention are able to beadapted to work with any data communications connections includingpresent day analog and/or digital techniques or via a future networkingmechanism.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof. The term “another”, as used herein,is defined as at least a second or more. The terms “including” and“having,” as used herein, are defined as comprising (i.e., openlanguage). The term “coupled,” as used herein, is defined as“connected,” although not necessarily directly, and not necessarilymechanically. “Communicatively coupled” refers to coupling of componentssuch that these components are able to communicate with one anotherthrough, for example, wired, wireless or other communications media. Theterms “communicatively coupled” or “communicatively coupling” include,but are not limited to, communicating electronic control signals bywhich one element may direct or control another. The term “configuredto” describes hardware, software or a combination of hardware andsoftware that is adapted to, set up, arranged, built, composed,constructed, designed or that has any combination of thesecharacteristics to carry out a given function. The term “adapted to”describes hardware, software or a combination of hardware and softwarethat is capable of, able to accommodate, to make, or that is suitable tocarry out a given function.

The terms “controller”, “computer”, “processor”, “server”, “client”,“computer system”, “computing system”, “personal computing system”,“processing system”, or “information processing system”, describeexamples of a suitably configured processing system adapted to implementone or more embodiments herein. Any suitably configured processingsystem is similarly able to be used by embodiments herein, for exampleand not for limitation, a personal computer, a laptop personal computer(laptop PC), a tablet computer, a smart phone, a mobile phone, awireless communication device, a personal digital assistant, aworkstation, and the like. A processing system may include one or moreprocessing systems or processors. A processing system can be realized ina centralized fashion in one processing system or in a distributedfashion where different elements are spread across severalinterconnected processing systems.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed.

The description of the present application has been presented forpurposes of illustration and description, but is not intended to beexhaustive or limited to the invention in the form disclosed. Manymodifications and variations will be apparent to those of ordinary skillin the art without departing from the scope of the invention. Theembodiment was chosen and described in order to best explain theprinciples of the invention and the practical application, and to enableothers of ordinary skill in the art to understand the invention forvarious embodiments with various modifications as are suited to theparticular use contemplated.

What is claimed is:
 1. In a processing system comprised of a server, amethod for the server to provide data values comprising: the servermaintaining a cache of objects; the server executing an asynchronouscomputation to determine the value of an object; in response to arequest for the object occurring before the asynchronous computation hasdetermined the value of the object, returning a value of the object fromthe cache of objects; and in response to a request for the objectoccurring after the asynchronous computation has determined the value ofthe object, returning a value of the object determined by theasynchronous computation.
 2. The method of claim 1 in which theasynchronous computation comprises at least one future.
 3. The method ofclaim 1 in which the asynchronous computation comprises at least oneprocess or thread.
 4. The method of claim 1 further comprising: inresponse to the asynchronous computation determining the value of theobject, updating the cache with the value of the object determined bythe asynchronous computation.
 5. The method of claim 1 in which saidstep of the server executing an asynchronous computation occurs inresponse to a request for the object.
 6. The method of claim 1 in whichsaid step of the server executing an asynchronous computation occursperiodically.
 7. The method of claim 1 in which said step of the serverexecuting an asynchronous computation occurs after a time interval haselapsed.
 8. The method of claim 1 in which said step of the serverexecuting an asynchronous computation occurs with a frequency correlatedwith how frequently the object changes.
 9. The method of claim 1 inwhich said step of the server executing an asynchronous computationoccurs with a frequency correlated with how important it is to have acurrent value of the object.
 10. The method of claim 1 furthercomprising at least one additional server wherein the asynchronouscomputation determines the value of the object by querying the at leastone additional server.
 11. The method of claim 10 further comprising theserver storing an object o2 in the cache of objects; the serverexecuting an asynchronous computation c2 to store object o2 on the atleast one additional server; and in response to receiving a request forobject o2 before asynchronous computation c2 has finished executing,satisfying the request from the cache of objects.
 12. The method ofclaim 10 in which said at least one additional server comprises aplurality of servers and the asynchronous computation receives differentvalues from at least two servers of the plurality of servers.
 13. Themethod of claim 12 in which the asynchronous computation determines thevalue of the object from a value which is returned most frequently bythe at least one additional server.
 14. The method of claim 12 in whichsaid different values have time stamps associated with them, and inwhich the asynchronous computation determines the value of the objectbased on the time stamps.
 15. The method of claim 10 further comprisingthe server executing an asynchronous computation c2 to store an objecto2 on the at least one additional server.
 16. The method of claim 15further comprising: in response to asynchronous computation c2 storingobject o2 on the at least one additional server, updating the cache ofobjects with the value of object o2.
 17. The method of claim 15 in whichasynchronous computation c2 includes an error handling method furthercomprising: in response to asynchronous computation c2 failing to storeobject o2, using the error handling method to retry storing object o2 onthe at least one additional server.
 18. A processing system comprising:a server; persistent memory; a network interface device forcommunicating with one or more networks; and at least one processor,communicatively coupled with the server, the persistent memory, and thenetwork interface device, the at least one processor, responsive toexecuting computer instructions, for performing operations comprising:the server maintaining a cache of objects in the persistent memory; theserver executing an asynchronous computation to determine the value ofan object; in response to a request for the object occurring before theasynchronous computation has determined the value of the object,returning a value of the object from the cache of objects; and inresponse to a request for the object occurring after the asynchronouscomputation has determined the value of the object, returning a value ofthe object determined by the asynchronous computation.
 19. Theprocessing system of claim 18, in which the asynchronous computationcomprises at least one future.
 20. The processing system of claim 18, inwhich the asynchronous computation comprises at least one process orthread.
 21. The processing system of claim 18, in which the at least oneprocessor, responsive to executing computer instructions, for performingoperations comprising: in response to the asynchronous computationdetermining the value of the object, updating the cache of objects withthe value of the object determined by the asynchronous computation. 22.The processing system of claim 18, in which the server executing theasynchronous computation occurs in response to a request for the object.23. The processing system of claim 18, in which the server executing theasynchronous computation occurs periodically.
 24. The processing systemof claim 18, in which the server executing the asynchronous computationoccurs after a time interval has elapsed.
 25. The processing system ofclaim 18, in which the server executing the asynchronous computationoccurs with a frequency correlated with how frequently the objectchanges.